Former Japanese Chris reincarnated in a different world as the third son of a poor aristocrat, dreaming of slow life. However, a letter arrives that his two older brothers will become mathematicians in the royal capital, and Chris will become the successor. When he checked the current situation as a lord, he found that the royal family's power had weakened, and the world was on the verge of war! Surrounded by great nobles, he’s doomed to be destroyed! “I’m determined to survive and live a slow life!”